Memories may be provided in a variety of apparatuses, such as computers or other devices, including but not limited to portable memory devices, solid state drives, music players, cameras, phones, wireless devices, displays, chip sets, set top boxes, gaming systems, vehicles, and appliances. There are many different types of memory including volatile memory (e.g., dynamic random access memory (DRAM)) and non-volatile memory (e.g., flash memory). Flash memory architectures may include NAND or NOR architecture.
Memory performance can be improved by compensating for variations in process, voltage, and temperature of the memory that may affect pre-driver circuit and driver circuit performance. Process variations are naturally occurring variations in the attributes of transistors that occur when integrated circuits are fabricated. Voltage variations may affect the final voltage and current output of the driver circuit. Temperature variations may affect the threshold voltages of transistors in the pre-driver circuit and driver circuit. Compensation for the effects of these variations can achieved by adjusting the ramping rate of a pre-driver circuit that supplies signals to a driver circuit. The pre-driver circuit may be configured to provide both a fast ramping rate corresponding to a higher output stage logic power voltage VCCQ, and a slower ramping rate corresponding to a lower VCCQ. The speed of the ramping rate in the pre-driver circuit that is provided with the higher VCCQ also generates higher noise in the final output of the driver circuit. Often it is not necessary to have this higher speed ramping rate, as the slower ramping speed is sufficiently fast. The pre-driver fast ramping rate corresponding to a higher data voltage out may be slowed down to more closely match the pre-driver slow ramping rate corresponding to a lower data voltage out. Because the ramping rates are more closely matched, the resultant current output from the pre-driver circuit may have a reduced sensitivity to variations in process, voltage, and temperature that may be present in the memory, and therefore transmit less noise to the final driver circuit output.